Chain.



Patented Mar. I3, i900. R. A. CARTER.

0 H Al N.

(Application filed Feb. 3, 1899.)

2 Sheets-Sheet I.

(No Model.)

FIE-3.4-

jinassis:

No. 645,202. Patented Mar. l3, woo.

' R. A. CARTER.

CHAIN.

(Application filed Feb. 3, 1899.)

' 2 Sheets$heet 2.

(No Model.)

ll/L4."- Wnvhnuiuuxk v UNITED STATES ROBERT A. CARTER, or PITTSBURG,PENNSYLVANIA.

CHAIN.

SPECIFICATION forming part of Letters Patent No. 645,202, dated March13, 1900. Application filed February 3, 1899. Serial No. 704,374. (Nomodel.)

To all whom, it may concern.-

Be it known that I, ROBERT A. CARTER, a citizen of the United States,residing at Pittsburg, in the county of Allegheny and State ofPennsylvania, have invented or discovered certain new and usefulImprovements in Chains, of which improvements the following is aspecification.

The invention described herein relates to certain improvements inchains, &c., and has for its object the formation of anantifrictionbearing between connected links, thereby avoiding allliability of any kinking or looking of the links out of line with eachother and also affording increased bearin g-surfaces between links.

The invention is hereinafter more fully described and claimed. 7

In the accompanying drawings, forming a part of this specification,Figure l is an elevation of my improved chain; Fig. 2 shows the links inelevation and section alternately. Figs. 3 and 4 are views similar toFigs. 1 and 2,illustrating a modification in the structure of the chain.Figs. 5 and 6 and 7 and 8 are views similar to Figs. 1 and 2,respectively, illustrating further modifications of my improvements. 1

In the construction shown in Figs. 1 and 2 the inner walls of the links1 1, &c., at and adjacent to the endsare grooved, thereby forming seats3 for the reception of the balls 2 2, &c. These balls, which are formedof hard steel or other suitable material, are interposed, as shown,between the ends of interlocking links, so that each link bears againsta ball and the engaging ends of adjacent links on opposite sides of thesame ball.

The grooves or seats in the inner walls of the links can be formed inanysuitable manner, but are preferably formed during the rolling of thebar from which the links are formed. In making the chain thebar-sections are bent to the desired shape and the ends welded in theusual or any suitable manner, the interlocking links being insertedprior to the welding of the ends of the link. If desired, the balls maybe placed in position prior to the complete closure and welding of thelink, or the link may be spread laterally after being welded, so as topermit of the insertion of the balls, and the sides then forced in, sothat the balls will be looselycaught in the grooves or seats, which notonly serve to retain the balls in position, but also afford broaderbearingsurfaces for the links. ,7 I

In case the links are braced transversely by struts 4 the edges of thelatter when the links are short are recessed for the reception of theinterlocking link 1; but sufficient space should be left to permit ofthe free lateral movement of the link. In addition to bracing the linktransversely the struts 4 serve to hold the balls in the seats 3 at theends of the links.

In some cases it may be desirable to employ balls of a diameter lessthan the distance between the inner walls of the sides of the links, asshown in Figs. 3 and 4. In such case provision is made for preventingthe lateral movement of one of the links to such an angular positionwith relation to the interlocking link as will permit of the ball beingshifted or permitted to drop out of position. This limitation of thelateral move ment of the links can be effected by the forniation ofshoulders 5 on the outer walls of the adjacent ends of links. Theseshoulders are made to project such a distance that when one of the linksis moved laterally one of its shoulders will bear upon the correspondingshoulder of the adjacent link and prevent any such further lateralmovement as would release the'ball. These shoulders are preferablyformed by thickening the walls at the ends of the links, as clearlyshown in Fig. 4, thereby increasing the strength of the links at theends. 7

In the construction shown in Figs. 5 and 6 alternate links 1 havegrooves extending entirely around the internal perimeter of the links,and the sides of such links are pressed in, so that the balls will beheld within the links at all points. The other links are made somewhatlarger as regards their internal width than the diameters of the balls.This construction imparts a greater flexibility to the chain. It ischaracteristic of this construction that the balls forming the bearingsof three interlocking links are held by the groove of the middle orholding link of each series of three.

In the construction shown in Figs. 7 and 8 each link is provided at oneend with a seat 6, in which the ball is retained by the abutments orshoulders at the ends of the groove or seat. The opposite end of thelinkis of the usual construction, except that its inner wall is slightlyconcave to afford a broader bearing on the ball held in the interlockinglink. As shown .in Figs. 7 and 8, the seat 6 is made to extend asufiicient distance along the inner wall of the link to surround alittle more than half the circumference of the ball.

It is characteristic of my improvement thatthe balls which are insertedbetween the bearing-surfaces of engaging or interlocking links permit ofan increase in area of such bearing-surfaces Without limitation of thefreedom of movement of the links. It is also characteristic of myinvention that provision is made for retaining the balls in operativeposition regardless of the relative positions of adjacent links.

I claim herein as my invention- 1. In a chain the combination of closedengaging or interlocking links of uniform size and shape provided withinternal concave grooves or seats for holding the balls within the linksand balls interposed between the ends of such links, substantially asset forth.

2. The combination of a chain consisting of closed links of uniform sizeand shape, balls interposed between the ends of the engaging orinterlocking links and'means for retaining the balls in operativepositions, substantially as set forth.

3. The combination in a chain of a series of engaging links, eachprovided with a concave seat at one end and shoulders or abut-

